The present disclosure generally relates to locomotion devices that can be used in conjunction with virtual reality systems.
Within a virtual reality environment, users typically desire the ability to walk freely. In particular, the ability to physically walk or run in the real environment and have that motion translated to the virtual environment significantly increases the level of immersion of the user in the virtual environment. However, movement in the real world is often limited by physical space limitations (e.g., the size of the room within which the user is located). Accordingly, locomotion devices are designed to provide the user the sensation of walking freely, while confining the user to a specific location. For example, many locomotion devices allow a user to walk freely, in 360 degrees, on a platform having a finite size without ever leaving the platform.
Conventional locomotion devices include motorized and non-motorized designs, which may be used in conjunction with virtual reality environments in a multitude of applications including but not limited to gaming. Examples of applications beyond gaming include employee training; combat training; physical therapy; exercise; virtual work environments; virtual meeting rooms (for both professional and personal purposes); sports simulation and training; and virtual tourism, concerts, and events.
Motorized locomotion devices typically use sensors to detect the movement of the user and send feedback to motors driving belts or rollers on which the user moves. The belts or rollers are operated to counter the user's movements and bring the user back to a central portion of the platform after each step. There are many drawbacks to motorized locomotion devices. For example, the motorized locomotion devices are usually complex and expensive because of the rolling and motorized components, sensors, processing units, and feedback loops. In addition, complex algorithms are required for the rolling and motorized components to properly counter the movements of the user. Inaccurate feedback to the motor can result in erroneous movement of the belts or rollers that may cause the user to lose balance or drift away from the center of the platform. There may also be issues with latency of feedback and response when the user accelerates, causing incorrect movements or responses that are too slow, potentially allowing the user walk off the platform. Further, because the response movements of the belts or rollers counteract the user's movements, the user may be prone to lose balance and trip.
In addition to issues with the operation of motorized locomotion devices, such devices are usually large and bulky, and thus, do not fit in the average-sized residential room (e.g., a game room, living room, or bedroom) and can be difficult to break up into modular pieces for shipping and storage. The devices are necessarily large, to prevent the user from walking off the platform before the correct system response has been processed; thus, rendering the devices unsuitable for in-home consumer usage.
Non-motorized locomotion devices lack motorized components and rely on the user's movement and/or gravity to bring the user back to the center of the platform after each step. Omni-directional ball bearing platforms, for example, have hundreds of ball bearings that allow the user to walk in place while a restraint around the user's waist keeps the user in place. A major issue with omni-directional ball bearing platforms is that the user does not experience a natural gait with a heel-toe strike movement, but rather instability similar to that of walking on ice. The instability results in the shuffling of feet where neither heel nor toe lift off the device, resulting in an unnatural walking gait that reduces the immersion of the user in the virtual environment. Moreover, these devices are typically heavy and expensive due to the plurality of rolling components.
Another non-motorized locomotion device is a saucer-like device with a smooth, upward facing concave surface. The user typically wears special shoes and then “walks” on the slick concave surface, repeatedly sliding his/her feet back and forth while his/her body remains primarily in the center of the device. Although saucer-like devices are relatively simple, small, and can fit in a residential room, there are several disadvantages. First, the user does not experience a natural gait with a heel-toe strike movement, but rather instability similar to that of walking on ice due to the low-friction properties of the concave surface and special shoes, which lack any foot-stabilizing elements. Thus, the user is forced to shuffle his/her feet to help maintain stability as opposed to employing a natural stepping motion. Further, there is no safety mechanism or device to prevent the user from falling during use.
Another non-motorized locomotion device is a large hollow spherical ball approximately 10 feet in diameter. The user enters the ball through a replaceable panel and walks within the ball as the ball rotates about its center relative to the surrounding environment. The ball device also has several issues. First, it is difficult and unnatural to start and stop movement of the ball, which may result in user instability. Further, because the size of the ball is necessarily constrained, the walking area is not planar, which also results in a less natural walking experience. In addition to the ball device being too large to fit in a residential room, such commercially available balls are also cost-prohibitive for household consumers.
Accordingly, there remains a need for locomotion devices that allow users to safely access virtual environments in the privacy of the user's home and while providing the sensation of a more natural walking gait.